This invention relates to fluid applicators that have multiple resolution capability, in particular to fluid applicators including ink jet print heads in combination with one or more other types of fluid dispensing mechanisms having various resolution and flow rate characteristics.
Various types of fluid applicators for dispensing a fluid, such as ink, adhesives, release materials, polymer based materials or other fluid materials, are currently available and usable for widely varying purposes. These applicators have utilized both contact and non-contact type techniques to apply a fluid to a substrate. In the printing area, these different techniques include contact methods such as flexographic printing and screen printing. In other fluid application areas, surface mount technology and robotics have been used to apply fluid in highly controlled and specific patterns. In recent years, major developments in the printing field have produced faster, better, cheaper and more user friendly printing devices for use with computer systems. The former mainstays of the computer printing area, dot-matrix printers and plotters, have given way to affordable personal laser printers and ink jet devices.
Ink jet imaging techniques have become very popular not only in devices for printing text, graphics and other images on flat sheet material, such as paper or film, but also in other commercial and consumer applications. Ink jet printers use a non-contact technique and operate by ejecting a fluid onto a receiving substrate in controlled patterns of fluid droplets. By selectively regulating the pattern of fluid droplets, ink jet printers can produce a wide variety of high resolution printed features, including text, graphics, images and holograms, using a wide variety of fluid materials, including various inks, adhesives and the like. Moreover, ink jet printers are capable of forming printed features on a wide variety of substrates, including not just flat films or sheets, but also three-dimensional objects as well.
Thermal ink jet printers and piezo ink jet printers are the two main types of inkjet systems in widespread use today. For both approaches, the fluid materials must meet stringent fluidic property requirements in order for the fluids to be appropriately jettable and for the resultant printed features to have the desired characteristics, such as mechanical, chemical, visual, and durability characteristics. In particular, the fluids must have relatively low viscosity when jetted, yet must be able to form accurate, durable images on the desired receiving substrate. The need to use low viscosity fluids makes it challenging to obtain printed features with the necessary characteristics.
Ink jet and ink-jet-style fluid applicators have been used to dispense numerous types of non-ink type fluids, including adhesives, plastics, wax, and ultraviolet (UV) curable materials, as well as a wide variety of other materials. In one case, an ink-jet-style selective deposition process was used with multiple print heads to build three dimensional models by depositing thermoplastic material, wax and bulk filling materials. In another case, multiple print heads were used in a drop-on-demand process to produce a wide variety of devices, including electronic devices, medical devices, and lenses, by selectively depositing various materials onto various substrates. In some situations, the multiple print heads are independently controlled and deposit different materials, however, in other situations the multiple print heads are controlled together or draw from a common reservoir.
Although extremely useful in a variety of applications, ink jet printing techniques include some drawbacks. The high resolution capability of the ink jet devices is achieved at the price of volumetric speed and coating thickness. Ink jet printers can be extremely slow relative to other types of fluid applicators. In situations where a large volume of fluid must be deposited, for example, ink jet printing becomes a less desirable technique. When speed and/or large volume deposition are desired, other types of print heads or fluid application techniques are commonly chosen, usually at a sacrifice of the resolution. There is, therefore, an ongoing need for fluid applicators that are capable of non-contact deposition of multiple types of fluid materials onto a variety of substrates, and that are capable of producing high resolution coatings with increasing thickness and volumetric speeds.
The present invention meets these requirements for more versatility in fluid deposition with a multiple resolution, non-contact fluid applicator capable of both high resolution and high throughput fluid deposition. The fluid applicator includes a fluid dispensing system for dispensing fluid material, a substrate handling system for positioning a substrate with respect to the fluid dispensing system and a control system for controlling the dispensing of the fluid material onto the substrate. The fluid dispensing system includes a first fluid dispensing mechanism that dispenses a first fluid material at a first resolution and a first throughput resulting in a coating having a first thickness. It also includes a second fluid dispensing mechanism that dispenses a second fluid material at a second resolution, throughput and coating thickness that may be different from the first resolution, throughput and coating thickness, respectively. The first and second fluid dispensing mechanisms use different fluid dispensing technologies to dispense the first and second fluid materials, respectively, therefrom. The control system positions the substrate and the first and second fluid dispensing mechanisms with respect to each other and controls the dispensing of the fluid materials onto the substrate in a predetermined pattern and with a controllable coating thickness and volumetric speed. Additional fluid dispensing mechanisms may also be used as needed to increase volumetric speed and coating rate for a desired coating material at a desired thickness, or may be used to achieve other functionality, such as a specific resolution.
The fluid dispensing mechanisms preferably include an ink jet print head capable of high resolution deposition of a fluid material. The high resolution mechanism may be used to deposit an accurate border that defines an article to be formed with the substrate. The fluid dispensing mechanisms also preferably include another jetting device, such as a stream jet and/or spray jet, typically capable of lower resolution but higher throughput deposition of a fluid material. The higher throughput device may then be used to rapidly fill in areas of the article with desired fluid as defined by the high resolution border.
The fluid applicator is capable of producing a large variety of articles including the substrate and deposited fluid materials. These articles preferably may include adhesive deposited by the fluid dispensing system, alone or in combination with other jettable materials.
A method of dispensing a fluid material at multiple resolutions and multiple throughput levels is also described including the step of providing a first fluid dispensing mechanism that dispenses a first fluid material at a first resolution and a first throughput using a first fluid dispensing technology. The step also includes providing a second fluid dispensing mechanism that dispenses a second fluid material at a second resolution that is different from the first resolution and a second throughput that is different from the first throughput using a second fluid dispensing technology that is different from the first fluid dispensing technology. The method also includes the steps of providing first and second fluid materials, providing a substrate onto which the first and second fluid materials are to be dispensed, and dispensing the first and second fluid materials onto the substrate in a predetermined pattern by contemporaneous activation of the first and second fluid dispensing mechanisms when positioned with respect to the substrate in a desired location. The method may also include providing additional fluid dispensing mechanisms and fluid materials, as well as the step of dispensing those additional materials.
In addition, a method of forming an article from a substrate and fluid material is described that includes the step of providing a first fluid dispensing mechanism that dispenses a first fluid material at a first resolution and a first throughput using a first fluid dispensing technology, and a second fluid dispensing mechanism that dispenses a second fluid material at a second resolution that is different from the first resolution and a second throughput that is different from the first throughput using a second fluid dispensing technology that is different from the first fluid dispensing technology. This method also includes the steps of providing first and second fluid materials, providing a substrate onto which the first and second fluid materials are to be dispensed, and dispensing the first and second fluid materials onto the substrate in a predetermined pattern by contemporaneous activation of the first and second fluid dispensing mechanisms when positioned with respect to the substrate in a desired location. In addition, the step of processing the first fluid material, second fluid material and substrate combination to produce an article, is also included.